Sablé is French for sand. Tuile is French for tile. They are named for their texture and shape respectively.
I make no apologies for including French biscuits in my list because they are delicious, although the best biscuit is the good old English malted milk. I'm not keen on custard creams (too sweet) but I do like chocolate digestives.
Wafers are sort of like a really really thin crispy waffle. Usually you get them in layers with some kind of soft-ish creme filling, like the kit-kat filling as Foote says.
But yes, you people need to come over here and be educated in the ways of the biscuit. We can have a biscuit party! We'll talk nonsense and eat biscuits until we're sick. It'll be awesome!